Modern motor vehicles nowadays have devices, actuated by external force or driven by motor, for moving (opening or closing) windows. Such devices comprise a motor unit as adjusting motor, which are provided in a motor vehicle door by means of a transmission mechanism and corresponding cables for moving the window. The assembly process in motor vehicles generally requires a modular configuration of the individual components, as in a window lifter. One module is formed by the motor unit which, within a housing, can have both an electric motor and also a corresponding transmission, wherein a second module, which can be designed as a plug-in module, can be connected to the module of the motor unit in order to provide current and to control the electric motor. To supply the motor with electrical energy or with electrical current, electrical contact elements are arranged in the housing or module of the motor unit and, when the plug-in module is inserted, they have to be electrically connected to corresponding motor contacts or electrical plug elements of the plug-in module. To achieve a low weight and to realize a predetermined shape for the plug-in module, the latter, or a housing thereof, is generally produced from a plastic. However, there is then the problem that the motor contacts or the electrical plug elements for contacting the electrical contact elements of the motor unit have to be arranged correctly and securely in the plastic structure of the plug-in module.